Date of Award


Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Advisor

Gary Schindler


Athletic Injuries -- physiopathology; Biomechanical Phenomena -- physiology; Risk Assessment; Risk Factors


Introduction: Athletes that participate in any sport are at an increased risk of injury, especially lower extremity injury. In particular, many athletes experience anterior cruciate ligament (ACL) injury during competition and practice sessions. The Landing Error Scoring System (LESS) is a tool used to identify athletes with a higher potential risk for ACL injury.

Purpose: The purpose of this study is to compare vertical jump landing mechanics between genders and among various sports.

Methods: Forty-one participants (21 females, 20 males) were recruited from a NCAA Division I university. Participants were from the following sports: football, volleyball, women’s soccer, and men’s and women’s basketball. Each participant had 18 markers placed on their bilateral (B) acromion, (B) greater trochanter, (B) mid-patella, (B) lateral knee joint line, (B) lateral malleoli, (B) posterior calcaneus, (B) base of 5th metatarsal, (B) 2nd MTP joint, and C7/L4 spinous processes. The VICON Motion Capture system was used to track joint angle displacement of a jump-landing task to identify at-risk landing mechanics. The jump-landing task was performed per the protocol of the LESS: participants jumped off a 30 cm box and landed at a distance of half of their height in front of the box; participants then immediately jumped vertically as high as they could and then landed. Participants were allowed two practice trials prior to three recorded trials.

Results: Four things were found to be significant when comparing between genders. Males had more trunk flexion at initial contact. Females had greater hip flexion at initial contact, medial knee position, and medial knee displacement. When comparing between female sports three things were found to be significant. Soccer had significantly less trunk flexion at initial contact compared to volleyball and basketball. Soccer had significantly more knee flexion displacement compared to volleyball. Volleyball had significantly less hip flexion displacement than both soccer and basketball. Comparing males sports one item was found to be significant. Basketball and significantly less knee flexion at initial contact than football.

Conclusion: The differences of jump mechanics found between genders may place females at a larger risk of sustaining a lower extremity injury compared to males. Soccer players were also seen to show the greatest risk of ACL injury compared to women’s basketball and volleyball players. Men’s basketball showed a greater risk of ACL injury compared to football. Future studies would benefit from recruiting a larger number of athletes to utilize the LESS in scoring athletes’ risk of sustaining a lower extremity injury.